Two animal experiments tested whether ibogaine and its synthetic version 18-methoxycoronaridine (18-MC) can block nicotine's effects in rats. Pretreatment with 18-MC significantly reduced nicotine-induced dopamine release in the brain's reward center, the nucleus accumbens. In a self-administration test, both compounds decreased rats' preference for nicotine for at least 24 hours. While ibogaine initially suppressed both nicotine and water intake, 18-MC selectively reduced nicotine consumption without affecting water intake. The results suggest 18-MC could be a prototype for a new smoking cessation treatment.
Ibogaine and two related compounds (noribogaine and 18-methoxycoronaridine) both inhibit and later enhance cocaine-induced hyperactivity in rats, depending on timing. When given 1 hour before cocaine, all three agents reduced the hyperactivity caused by cocaine. When given 19 hours before cocaine, they instead amplified it. These opposite, time-dependent effects explain conflicting findings in earlier research and were not caused by the drugs' own effects on movement.